Functionalization of polymers via enamine of acetoacetate

ABSTRACT

The present invention relates to the preparation of polymers bearing reactive functional groups. More particularly, this invention relates to the preparation of polymers containing functional acetoacetate groups and then following the polymerization reacting the acetoacetate group with a functional amine to form an enamine. 
     Polymers of the present invention have many uses including coatings, sealants, adhesives and saturant applications, and are most useful as solutions or dispersions in water or water-cosolvent mixtures.

FIELD OF THE INVENTION

The present invention relates to the preparation of polymers bearingreactive functional groups. More particularly, this invention relates tothe preparation of polymers containing functional acetoacetate groupsand then following the polymerization reacting the acetoacetate groupwith a functional amine to form an enamine.

Polymers of the present invention have many uses including coatings,sealants, adhesives and saturant applications, and are most useful assolutions or dispersions in water or water-cosolvent mixtures.

Coatings produced from polymers of the present invention exhibitimproved properties such as, for example, solvent resistance, dirtpickup resistance, print and block resistance, mar resistance, adhesionand tensile properties, such as impact resistance and tensile strength.

BACKGROUND OF THE INVENTION

It is generally known to be useful to modify the properties of polymersby incorporating desired functional groups of one sort or another intothe polymer molecules. The desired functional groups may be incorporatedeither by employing, as a monomer during the preparation of the polymer,a compound which already has such functional groups, or by post-reactingthe polymer having precursor groups with suitable reagents to convert tothe desired functional groups.

A novel, unanticipated and useful process is now discovered forpost-reacting a polymer having precursor groups for purpose ofincorporating desired functional groups into a polymer.

An advantage of the invention is to provide a process which produces afunctional polymer by post-polymerization reaction.

Another advantage of the invention is to provide new monomers bearingfunctional groups.

An additional advantage of the invention is to provide polymers bearingfunctional groups which are incompatible with polymerization processes.

PRIOR RELATED ART

Although it is generally known to modify the properties of polymers byincorporating desired functional groups, none of the related artdiscloses the preparation of polymers containing functional acetoacetategroups, and postpolymerization reacts the acetoacetate group with afunctional amine to form an enamine.

European Patent Application EP 0 442 653 A2 discloses a process for theproduction of a polymer having desired groups, denoted as Y, by reactinga polymer having carbon or nitrogen-bound-NH₂ and/or --NH₂ -- precursorgroups, which groups are reactable with enolic carboxyl groups, with atleast one compound having a single enolic carboxyl group and at leastone Y, wherein by an enolic carbonyl group is meant a carboxyl grouphaving enolic character by virtue of being bonded to an alpha methyleneor methane group which is itself bonded to an electron withdrawinggroup.

European Patent Application EP 0 483 583 A2 discloses thatpolyacetoacetates or polyacetoaceteamides can be reacted with aminogroup-containing alkoxy-silanes to give polyenamines which permit a longprocessing time and which crosslink without the action of atmospherichumidity. This is alleged to be an advantage for film thickness greaterthan 50.sub.μ.

SUMMARY OF THE INVENTION

In one aspect of the invention, an acetoacetate functional polymer isreacted with a compound bearing an amine group and at least oneadditional functional group, to produce a polymer bearing the additionalfunctional group attached through the enamine of the acetoacetate group.

In another aspect of the invention, acetoacetate functional monomer isreacted with a compound bearing an amine group and at least oneadditional functional group, to produce a new functional monomer. Thismonomer can be subsequently polymerized to form a functionalizedpolymer.

DETAILED DESCRIPTION

In one aspect of the invention, an acetoacetate functional polymer isreacted with a compound bearing an amine group and at least oneadditional functional group, to produce a polymer bearing the additionalfunctional group attached through the enamine of the acetoacetate group.

In another aspect of the invention, acetoacetate functional monomer isreacted with a compound bearing an amine group and at least oneadditional functional group, to produce a new functional monomer. Thismonomer can be subsequently polymerized to form a functionalizedpolymer.

In still another aspect of the invention, polymers prepared bypolymerizing acetoacetate functional monomers are reacted with acompound bearing an amine functional group and at least one incompatiblefunctional group, a group which would not have maintained functionalviability under the conditions of the polymerization process. A newpolymer is produced, bearing the incompatible functional group attachedto the polymer via the enamine of the acetoacetate group.

In a further aspect of the invention, a polymer functionalizationpackage and a method of functionalizing is provided. Acetoacetatefunctional polymer backbones can be prepared, and the proportion ofcompound bearing an amine group and at least one additional functionalgroup can be varied over a range from about a molar excess of amine,based on acetoacetate, to substantially less than a molar excess, to fitthe particular property requirements of the end use application. Thisallows one to maintain an inventory of relatively few types ofpolymerization products and offer a diverse line of end use polymers bycustom-functionalizing the polymers with the selected amount of aminefunctional reactant.

In still a further aspect of the invention, a method is provided whichallows the incorporation of desired functional groups, concentrated indesired areas, for example, at the surface of a polymer particle.

Polymers bearing functional groups attached through the enamine ofacetoacetate groups are useful in coatings, adhesives, polymer blends,plastics additives, dispersants, flocculants and separationtechnologies.

Polymers

The preferred polymers for use in this invention are vinyl polymers withpendant acetoacetate groups, alternately known as beta-ketoesters. Theterm "pendant" is used in the specification to mean "attached to thepolymer backbone and available for further reaction." Pendant should notbe read in the strict sense which would exclude the attachment of suchgroups at the termini of a polymer chain. Thus, polymer havingacetoacetate functionality introduced on the chain end by anacetoacetate functional mercaptan, as taught in U.S. Patent 4,960,924,would be useful in this invention. Generally, the pendant acetoacetategroups are attached to the polymer backbone via an organic divalentradical R¹ which in turn is attached to the acetoacetate moiety or by atrivalent organic radical R² bearing two acetoacetate groups. ##STR1##

The acetoacetate functional polymers can be prepared by means known inthe art. A preferred method is polymerization through incorporationwhich includes an acetoacetate functional monomer. A preferred monomeris acetoacetoxyethyl methacrylate which is conveniently referred tothroughout this specification as AAEM, shown below. ##STR2##

Examples of other monomers useful for introduction of acetoacetatefunctionality are acetoacetoxyethyl acrylate, acetoacetoxypropylmethacrylate, allyl acetoacetate, acetoacetoxybutyl methacrylate,2,3-di(acetoacetoxy)propyl methacrylate, and the like. In general, anypolymerizable hydroxy functional monomer can be converted to thecorresponding acetoacetate by reaction with diketene or other suitableacetoacetylating agent (See e.g. Comparison of Methods for thePreparation of Acetoacetylated Coating Resins, Witzeman, J. S.; DellNottingham, W.; Del Rector, F. J. Coatings Technology; Vol. 62, 1990,101. (and references contained therein)).

The vinyl polymers of this invention are most often copolymers of theacetoacetate functional monomer and other monomers. Examples of usefulcomonomers are simple olefins such as ethylene, alkyl acrylates andmethacrylates where the alkyl group has 1 to 20 carbon atoms (morepreferably 1 to 8 carbon atoms), vinyl acetate, acrylic acid,methacrylic acid, acrylonitrile, styrene, isobornyl methacrylate,acrylamide, hydroxyethyl acrylate and methacrylate, hydroxypropylmethacrylate and acrylate, N-vinyl pyrolidinone, butadiene, isoprene,vinyl halides such as vinyl chloride and vinylidene chloride, alkylmaleates, alkyl fumarates, fumaric acid, maleic acid, itaconic acid, andthe like. It is also possible and sometimes desirable to include lowlevels of divinyl or polyvinyl monomers such as glycol polyacrylates,allyl methacrylate, divinyl benzene, and the like, to introduce acontrolled amount of gel in the latex particle. It is important,however, to be sure that when this is done, the quality of the filmformation is not seriously impaired. Additionally, one may wish toinclude chain transfer agents to control molecular weight of thepolymer.

The acetoacetate functional polymer may contain from about 0.5% to 100%of the acetoacetate functional monomer by weight. In any application,the amount of acetoacetate functional monomer required will vary fromcase to case depending upon the desired degree of post functionalizationnecessary for the particular end-use application. Generally, however,the acetoacetate monomer concentration will be between 1 and 40%.Conventional coatings will usually contain from about 0.5 to 20%acetoacetate monomer by weight. Polymers having a molecular weight offrom 1,000 to over one million can be used. The lower molecular weightpolymers should contain a sufficiently high level of acetoacetate tomaximize the degree of post functionalization. For example, a copolymerof AAEM having a molecular weight under 10,000 would typically contain30% or more of AAEM.

Generally, the vinyl polymer is prepared as a dispersion or emulsionpolymer in water by a suitable free radical initiated polymerizationtechnique, using a free radical initiator and appropriate heating. Sincea film-forming polymer is sometimes desired, useful emulsion polymerswill generally have glass transition temperatures under 60° C., sincethese polymers with coalescent will form good quality films at ambienttemperatures. If soluble polymers are used in the film formationprocess, polymers of higher glass transition temperature are readilyused since they are film-forming.

In certain aspects of the invention, polymerization in an aqueous mediumand, in particular, aqueous emulsion polymerization, is used to preparethe polymer. Conventional dispersants can be used (e.g. anionic and/ornonionic emulsifiers such as alkali or ammonium alkyl sulfates, alkylsulfonic acids, and fatty acids, oxyethylated alkyl phenols, and thelike). The amount of dispersant used is usually 0.1 to 6% by weightbased on the weight of total monomer. Either thermal or redox initiationprocesses may be used. Conventional free radical initiators may be used(hydrogen peroxide, organic hydroperoxides such as t-butylhydroperoxide, cumene hydroperoxide, t-amyl hydroperoxide, ammoniumand/or alkali persulfates, organic peroxides such as t-butylperpivalate, t-butyl perbenzoate, benzoyl peroxide, di(n-propyl)peroxydicarbonate, acetyl cyclo-hexylsulfonyl peroxide, and the like);typically 0.05 to 3.0 % by weight based on the weight of total monomer.Redox systems using the same initiators coupled with a suitablereductant (for example: reducing sugars such as isoascorbic acid, sodiumbisulfite, sodium thiosulfate, hydroxyl amine, hydrazine, sodiumhydrosulfite) can be used at similar levels, oftentimes in conjunctionwith a metal catalyst such as salts of transition metals, examples ofwhich are iron sulfate, copper sulfate, vanadium sulfate, and the like.Additionally, non-oxidizing thermal initiators such as2,2'-Azo-bis-isobutyronitrile, 4,4'-Azo-bis(4-cyanopentanoic acid),2,2'-Azo-bis(2-amidinopropane) dihydrochloride, and the like.Frequently, a low level of chain transfer agent such as a mercaptan (forexample: n-octyl mercaptan, n-dodecyl mercaptan, butyl or methylmercaptopropionate, mercaptopropionic acid at 0.05 to 6% by weight basedon total weight of monomer) is employed to control molecular weight.

The invention may also be practiced using a solvent-soluble orwater-soluble polymer. When this is desired, the polymer may be prepareddirectly in water if the monomer mix is water-soluble or, as is mostoften the case, the polymerization solvent is a water miscible solventsuch as isopropanol, butyl cellosolve, propylene glycol, and the like.In this case, water may be included in the polymerization mixture orpost added after the polymerization is complete. In some cases, thepolymer is prepared in a conventional organic solvent such as xylene,butyl acetate, methyl ethyl ketone, methyl tertiary butyl ether, and thelike. When organic solvent is employed with or without water, it isconvenient to use organic soluble-free radical initiators such asazo-bis-isobutyronitrile, t-butyl-peroctoate, or benzoyl peroxide andwhatever heat is convenient to assure smooth copolymerization. Anotherroute to preparation of a water-soluble polymer for this invention is toprepare a vinyl dispersion polymer having enough acrylic or methacrylicacid or other polymerizable acid monomer (usually greater than 10%) sothat the emulsion polymer can be solubilized by addition of ammonia orother base. Water-soluble polymers of this type are advantageously usedas blends with conventional dispersion polymers, preferably those whichalso have pendant acetoacetate functionality. The blend ofalkali-soluble resin and latex polymer has a particularly advantageousproperty combination of gloss and rheology and is useful in coatings andprinting ink applications.

In another embodiment of this invention, an aqueous dispersion containscopolymer particles made up of at least two mutually incompatiblecopolymers. These mutually incompatible copolymers may be present in thefollowing morphological configurations, for example, core / shell, core/ shell particles with shell phases incompletely encapsulating the core,core/shell particles with a multiplicity of cores, interpenetratingnetwork particles, and the like. In all of these cases, the majority ofthe surface area of the particle will be occupied by at least one outerphase and the interior of the particle will be occupied by at least oneinner phase. The mutual incompatibility of the two polymer compositionsmay be determined in various ways known in the art. The use of scanningelectron microscopy using staining techniques to emphasize thedifference between the appearance of the phases, for example, is such atechnique.

The emulsion polymerization techniques used to prepare such dispersionsare well known in the art. It is sometimes advantageous to introducesome crosslinking or gel structure by the sequential polymerizationprocess in the core via low levels of a crosslinking monomer such asallyl methacrylate, diallylphthalate, diallyl maleate, butylene glycoldimethacrylate, divinyl benzene, triallyl isocyanurate, ethylene glycoldiacrylate, and the like. The lightly crosslinked core does notadversely affect film formation and does in some cases result in bettercoatings, particularly when the pendant acetoacetate is concentrated inthe shell.

As indicated above, a major use for this technology is forfunctionalizing vinyl polymers dispersed or dissolved in aqueoussolvents. Unfortunately, vinyl polymers containing pendant acetoacetateare prone to hydrolysis in water, particularly on heat aging. Thehydrolysis occurs at nearly any pH and yields acetoacetic acid, ##STR3##which in turn decomposes to acetone and carbon dioxide.

In an earlier application, U.S. Ser. No. 632,302, abandoned, thesolution to this problem was provided by treating the aqueousacetoacetate polymer after preparation with one molar equivalent ofammonia or a primary amine such as ethanolamine, methyl amine, orisopropyl amine. As described in that application, typically, thepolymer is neutralized to a basic pH with one of the aforementionedamines, preferably to a pH greater than 9. Under these conditions theenamine is formed. The reaction to form the enamine is generally rapidwith the rate of formation increasing with temperature. In general,enamine formation is complete within 8 hours. An alternative approach isto raise the pH to about 9, allow the system to equilibrate, andreadjust the pH to about 9 to replace the amine consumed by enamineformation. The enamine is stable to hydrolysis at pH's typically greaterthan 7.

We have now found that the enamine reaction route provides a method ofattaching additional functional groups, or functionalized side chains toacetoacetate polymers. As shown in the following formula in which R²represents a functional group or a linking group which bears afunctional group. ##STR4##

Sterically hindered primary amines such as t-butyl amine and aromaticamines such as aniline are generally less suitable because of incompleteenamine formation. The enamine formation is a reversible reaction so theamine compound should be non-volatile if the composition is likely to beexposed to the atmosphere prior to the application use of the functionalgroup. The wet composition is quite storage stable, however, as long asit is stored under conditions (such as a closed container) where thevolatile amine cannot evaporate.

Another approach to preparation of vinyl polymers containing equivalentpendant enamine functionally is to use preformed enamine monomersderived from the appropriate amine and the acetoacetate monomer. In thiscase, the pH must be kept on the alkaline side during polymerization toavoid hydrolysis of the enamine back to the acetoacetate.

Functional Groups

In the formula --R² NH₂, R² can be a functional group, or a linkinggroup bearing a functional group. Examples of linking groups aredivalent groups such as C₂ to C₁₈ alkyl, alkoxyl and polyalkoxyl, suchas polyoxyethylene and polyoxypropylene chains, having molecular weightsof from about 72 to about 400,000.

Examples of types of property-imparting functional groups which may beattached through this method include crosslinking groups, adhesionpromoters, ultraviolet blocking groups, surface active compounds, latexstabilizing groups, binding groups for separation, etc. Functionalgroups of this type are well known in the art such as, for example,mercaptoethyl amine, taurine, 3-aminopropyltrimethoxysilane,3-aminopropyltriethyoxysilane, polyoxypropyleneamine,polyoxyethyleneamine, 2-aminoethylethyleneurea,2-dimethylaminoethylamine, amino acids, allylamine,4-amino-2,2,6,6-tetramethylpiperidinyloxy-free radical, and the like.

In one embodiment, the compound bearing amine functionality and anadditional functional group contains both primary amine functionality,for enamine formation, and a secondary or tertiary amine functionality.In the case of the tertiary amine, a route to a cationic latex isprovided; when the tertiary amine functional polymer is treated with aproton source or alkylating agent, an ammonium cation can be produced.

A sterically stabilized latex can be produced for example throughreaction of an acetoacetate polymer with a polyethoxylated amine. Thistechnique also provides a route to control the polarity of the polymerby selecting from hydrophilic or hydrophobic amines. Similarly, therefractive index of the polymer can be adjusted using appropriatefunctional group on the amine to either raise or lower the refractiveindex. The compatibility of various pairs of polymers could also beimproved for blending by adding selected functionalities on one or bothpolymers.

Monomers bearing certain functional groups are not generally suitablefor incorporation into polymers, either due to the likelihood that thefunctionality would be chemically altered under the conditions ofpolymerization, or due to the tendency of the functional group toproduce an undesired effect on the polymerization process. For example,a mercaptan functional group could cause a chain transfer effect duringfree radical polymerization, thus skewing the product profile towardlower molecular weight products than if a functionality that does nothave a chain transfer effect were used. An olefinic functional group islikely to be consumed in a free radical polymerization process, butcould be post-added according to the invention. A secondary amine cancause retardation and chain transfer during free radical polymerization.

Additives

The polymers and additives of this invention may be formulated for thechosen end use. Additives such as thickeners, dispersants, pigment,extenders, fillers, anti-freeze agents, plasticizers, adhesionpromoters, coalescents, wetting agents, defoamers, colorants,non-aldehyde based biocides, soaps and slip agents may be incorporated.

The following examples are provided to illustrate some embodiments ofthe invention. They should not be read as limiting the scope of theinvention which is more fully described in the specification and claims.

Unless otherwise indicated, percentages are by weight based on the totalsolids.

EXAMPLE 1

A polymer was prepared from a monomer mixture that contained 501.7 gramsof water, 18.1 grams of Rhodapex CO-436 (an ammonium salt of sulfatednonylphenoxypoly (ethyleneoxy) ethanol; RhOne Poulenc), 7.5 grams ofmethacrylic acid, 597.6 grams of acetoacetoxyethyl methacrylate, 888.9grams of methyl methacrylate, and 44.9 grams of n-dodecyl mercaptan.From this monomer emulsion mixture, 47.2 grams was removed and added toa kettle containing a mixture of 1317.9 grams of water and 8.74 grams ofRhodapex CO-436 heated to 85° C. An initiator charge of 2.26 grams ofsodium persulfate dissolved in 50.0 grams of water was added. Startingten minutes later, the remaining monomer emulsion was gradually addedover a two hour period along with 1.13 grams of sodium persulfatedissolved in 50 grams of water in a separate feed. After the two hourperiod, the emulsion was cooled to ambient temperature.

Solubilization of Polymer

To 500 grams of the emulsion which was reduced to 41.8% solids withwater was added 370 grams (0.95 equivalents based acetoacetatefunctionality) of a 1000 molecular weight primary amine terminatedpolyethoxylate (Jeffamine M-1000, Texaco). The resulting mixture becamea clear solution of a highly viscous material (Brookfield viscosity of7160 cps) with solution like rheology.

This example illustrates that, with the appropriate amine, emulsionpolymers can be solubilized to form uniform solution resins by enamineformation.

EXAMPLE 2

A polymer was prepared from a monomer mixture that contained 501.7 gramsof water, 45.7 grams of a 23% solution of sodium dodecyl benzenesulfonate, 19.42 grams of methacrylic acid, 298.8 grams ofacetoacetoxyethyl methacrylate, 578.2 grams of methyl methacrylate,597.6 grams of butyl acrylate and 3.0 grams of n-dodecyl mercaptan. Fromthis monomer emulsion mixture, 47.2 grams was removed and added to akettle containing a mixture of 1317.9 grams of water and 22.0 grams ofthe sodium dodecyl benzene sulfonate solution heated to 85° C. Aninitiator charge of 2.26 grams of sodium persulfate dissolved in 50.0grams of water was added. Starting ten minutes later, the remainingmonomer emulsion was gradually added over a two hour period along with1.13 grams of sodium persulfate dissolved in 50 grams of water in aseparate feed. After the two hour period, the emulsion was cooled toambient temperature. To aliquots of the emulsion was added 1 equivalentof the amine listed in Table A. The latex polymers were equilibrated fortwo days prior to freeze drying and the Tg of the polymer was determinedby differential scanning calorimetry.

                  TABLE A                                                         ______________________________________                                        Effect of Formation of Enamines on the Tg of the Polymer                      Amine                  Tg (°C.)                                        ______________________________________                                        control (none)         23                                                     ammonia                26                                                     ethanolamine           30                                                     4-amine-2,2,6,6-tetramethylpiperidine                                                                39                                                     ______________________________________                                    

This example illustrates that the Tg of the polymer can be adjustedafter polymer formation by post addition of the selected primary amineand formation of the corresponding enamine.

EXAMPLE 3

Functional Monomer I (ethylethyleneureaenamine of allyl acetoacetate)

A functionalized monomer was prepared by treating allylacetoacetate (77gm, 0.543 moles) with aminoethylethyleneurea (70 gm, 0.543 moles) in 149grams of ethylacetate containing 0.4 grams of phenothiazine. Thereaction mixture was heated to reflux while connected to a Dean-Starktrap (used to azeotropically remove water) for a total of 13 hours. Thereaction solvent was then removed under reduced pressure using arotoevaporator yielding a total of 122 grams of product:

EXAMPLE 4

Functional Monomer 2 (hydroxyethylenamine of AAEM)

A functionalized monomer was prepared by treatingacetoacetoxyethylmethacrylate (AAEM) (200 gm) with ethanolamine (62.7gm) in 500 gm of methylene chloride. The reaction mixture was stirred atroom temperature for 20 minutes then heated to reflux for 1 hour thencooled to room temperature. The cooled reaction mixture was poured intoa separatury funnel and washed twice with saturated sodium chloridesolution. The organic solution was then dried using anhydrous potassiumcarbonate. The dried organic solution was filtered to remove thepotassium carbonate. The resulting organic solution was thenconcentrated under reduced pressure using a rotoevaporator to yield 239grams of the desired product: 1H NMR (270 MHz, CDCL3) d 1.85 (br s, 6H),3.3 (br q, 2H), 3.62 (br t, 2H), 3.8 (m, 1H), 4.2 (m, 4H), 4.38 (s, 1H),6.02 (s, 1H), 8.5 (m,1H).

EXAMPLE 5

Preparation of Solution Polymer Using an Enamine Functionalized Monomer

A reaction flask containing 286 grams of xylene was heated to 105° C.under a nitrogen atmosphere. A mixture of 120 grams ofbutylmethacrylate, 67 grams of butylacrylate, 10 grams of the enamineformed from. (AAEM and ethanolamine in Example 4), and 3 grams ofmethacrylic acid was feed to the reaction kettle concurrently with amixture of 6 grams of t-butylperoctoate dissolved in 14 grams of xyleneover a period of 2 hours. The reaction was then held at 105° C. for anadditional 30 minutes at which time 0.5 grams of t-butylperoctoate wasadded to the reaction mixture. The reaction was held an additional 10minutes at 105° C. then cooled to room temperature. The final solutionwas shown to contain 38% by weight solid polymeric material by drying asample in an oven at elevated temperature (150° C. for 30 minutes). Thepolymer was shown to contain the enamine structure by taking a UVspectra of a thin film of the polymer cast on a quartz disk. The UVspectra contained a large absorption characteristic ofbetaaminocrotonates at a wavelength of 283 nm.

EXAMPLE 6

Vinyl Acetate Emulsion Polymer

An emulsion polymer of overall composition 96.45 vinyl acetate/3.3allylacetoacetate/0.25 sodium vinylsulfonate was prepared by adding amonomer mixture that contained 490 grams of water, 1.8 grams of a 58%solution of the ammonium salt of nonylphenoxypolyethylenoxidesulfonate(Rhodapex CO-436), 3 grams of acetic acid, 3.6 grams of sodium acetate,2083.4 grams of vinyl acetate, 21.6 grams of sodium vinylsulfonate, and71.3 grams of allyl acetoacetate to a reaction kettle containing 1026grams of water (heated to 60° C. ), 60 grams of a 45% solutioncontaining 100 nm particles of a BA/MMA/MAA latex polymer, 24 grams of a2.75% aqueous solution of sodium persulfate, 24 grams of a 1.25% aqueoussolution of sodium bisulfite,. 12.0 grams of a 0.2% aqueous solution offerrous sulfate, 3 grams of acetic acid, and 3 grams of sodium acetate.The above monomer emulsion was fed into the reaction kettle concurrentlywith a solution of 120 grams of 2.25% sodium bisulfite and a solution of2.4 grams of t-butylhydroperoxide, 1.8 grams of sodium persulfate, and120 grams of water over a period of 3.5 hours under a nitrogenatmosphere. Following the addition of monomer, the reaction wasmaintained at 60° C. for 15 minutes then a solution of 30 grams of 8%aqueous t-butylhydroperoxide was added to the kettle along with asolution of 120 grams of 5% aqueous isoascorbic acid. The reaction wasthen cooled to room temperature to yield a latex containing 51.6% solidspolymer.

EXAMPLE 7

Functionalization of a Vinyl Acetate Emulsion

A sample of 100 grams of emulsion polymer from Example 6 was treatedwith 1.55 grams of aminoethylethyleneurea. The reaction was held at roomtemperature. The next morning, a thin film of the polymer on a quartzdisk was shown to contain the UV absorption peak characteristic of thebeta-aminocrotonate structure at a wavelength of 280 nm).

EXAMPLE 8

(Meth)acrylate Emulsion Polymer

A polymer was prepared from a monomer mixture that contained 629.99grams of water, 9.89 grams of a 23% aqueous solution of sodiumdodecylbenzene sulfonate, 790.02 grams of butyl acrylate, 686.57 gramsof methyl methacrylate, 376.20 grams of acetoacetoxyethylmethacrylate,and 28.22 grams of methacrylic acid. From this monomer emulsion, 58.72grams was removed and added to a reaction kettle heated to 85° C.containing 1577.93 grams of water, 8.22 grams of a 23% aqueous solutionof sodium dodecylbenzene sulfonate, 3.02 grams of sodium persulfate. Themonomer emulsion was added to the kettle concurrently with 50 grams of a1.7% aqueous solution of sodium persulfate over 180 minutes. Followingthe additions, the reaction was held at 85° C. for 30 minutes thencooled to 65° C. When the reaction mixture reaches 65° C. 1.0 grams of a0.48 aqueous solution of ferrous sulfate, 0.54 grams of 70% activet-butylhydroperoxide dissolved in 19 grams of water, and 0.38 grams ofisoascorbic acid dissolved in 19 grams of water are added to thereaction kettle. The reaction is held at 65° C. for 15 minutes and thereaction cooled to room temperature. this produced an emulsion polymerat 43.3 % solids.

EXAMPLE 9

Preparation of a Cationic Latex

A 10 gram sample of experimental latex prepared in Example 8 was dilutedwith 33.3 grams of 0.1 molar potassium chloride and 0.18 grams of TritonX-405 (a 70% aqueous solution, from Union Carbide). This latex samplewas then treated with 0.356 grams of dimethylaminoethylamine andequilibrated overnight. The acoustophoretic mobility was measured whilevarying the pH of the system using a Penkem 7000 instrument. Therelative acoustophoretic mobility (RAM) was approximately -1.8-10⁻¹⁰from pH 10 to 8.5, from pFI 8 to 2 the RAM was +1.2×10-10. This clearlydemonstrates that the latex is anionic (negatively charged) at high pHsand cationic (positively charged) at low pHs, where the tertiary aminegroup is either uncharged or protonated respectively, and therefore thetertiary amine group must be attached to the latex particles.

EXAMPLE 10

Latex polymer A is a two stage emulsion polymer of composition 50 (542-ethylhexyl acrylate/2.0 styrene/25 acrylonitrile/4 methacrylic acid/15acetoacetoxyethylacrylate)//50 (40 isobutylmethacrylate/58methylmethacrylate/2 methacrylic acid) at 39.7% solids. Latex B is a twostage emulsion polymer of composition 50 (3 butylacrylate/91.6styrene/4.4 divinylbenzene/1 methacrylic acid)//50 (83 butylacrylate/10acetoacetoxyethylacrylate/7 methacrylic acid) at 41.6% solids, both ofwhich are prepared via conventional techniques well known in the art.The below listed examples are prepared by taking a sample of latex (100gm) and treating it with butyl cellosolve (8.93 gm) and butyl Carbitol(2.98 grams) then adding the appropriate amount of the listed functionalamine.

    ______________________________________                                                                    MEK   Acetone                                                                              Print                                                            Swell Spot   Resist-                              Amine      Amount   Latex   Ratio Test   ance                                 ______________________________________                                        none (control)                                                                           0        A       7.3   1      3                                    2-(2-aminoethyl)-                                                                        1.45     A       4.5   5      7                                    aminoethanol                                                                  4-amino-2,2,6,6-                                                                         2.17     A       5.1   N/A    9                                    tetramethyl-                                                                  piperidine                                                                    none (control)                                                                           0        B       4.5   0      4                                    2-(2-aminoethyl)-                                                                        1.01     B       3.8   4      7                                    aminoethanol                                                                  N-methyl   1.13     B       3.3   9      5                                    ethylenediamine                                                               2-((3-aminopropyl                                                                        0.86     B       3.4   6      7                                    amino)-propane1                                                               N-ethyl    0.72     B       3.3   6      4                                    ethylenediamine                                                               ______________________________________                                    

The above examples demonstrate that the use of diamines (where one amineis a primary amine and the other amine is a secondary amine) can improvethe solvent resistance and print resistance of clear coatings for use onwood, as well as other solid substrates.

TEST METHODS

Print Resistance Test

A film is cast 1 mil DFT on aluminum and air dried for 4 hrs. A piece ofcheesecloth is placed on the film and a weight is placed on thecheesecloth to give a pressure of 4 psi. After 4 hrs., the weight andcheesecloth are removed and the film is examined for any impression madeby the cheesecloth. The samples are rated on a 0 to 10 scale, where 0represents complete failure, with the cheesecloth irreversibly adheredto the coating, and a 10 being no visual damage to the coating when thecheesecloth is removed.

Acetone Spot Test

A film is cast 1 mil DFT on aluminum and air dried for I week. A glassfiber filter disk (Gelman 66075 or equiv.) is soaked in acetone and thenplaced on the film and covered with a watch glass. After 2 minutes, thefilter is removed, the excess acetone is blotted off with a tissue, andthe film is examined for any damage. The samples are rated on a 0 to 10scale, where a 0 represents a complete failure with the coatingdissolving in the solvent and a 10 representing a coating having novisual damage.

MEK Swell Ratio Test

A film of the latex polymer, approximately 10 to 12 mils thickness wetleading to a dry film thickness of approximately 2 mils dry, is castonto a sheet of polypropylene. The dry film is removed from thepolypropylene and cut into a 1 cm by 1 cm square sample. The sample issoaked in methylethylketone for 2 hours. The swollen sample is removedfrom the solvent and the length of one edge is measured. The resultinglength is then cubed to give the reported swell value. A lower valuerepresents inherently better solvent resistance of the coating.

GLOSSARY

When used in this application, the abbreviations shown in the followinglist have the meanings indicated:

The Tg of a polymer is a measure of the hardness and melt flow of thepolymer. The higher the Tg, the less the melt flow and the harder thecoating. Tg is described in Principles of Polymer Chemistry (1953),Cornell University Press. The Tg can be actually measured or it can becalculated as described by Fox in Bull. Amer. Physics Soc., 1,3, page123 (1956). Tg, as used herein, refers to actually measured values. Formeasurements of the Tg of a polymer, differential scanning calorimeter(DSC) can be used (a rate of heating of 10 degrees centigrade perminute, with Tg taken at the first inflection point).

DFT is the Dry Film Thickness.

We claim:
 1. A process for producing storage stable functional polymerscomprising reacting an aqueous acetoacetate-functional polymer with acompound which has primary amine and at least one other type offunctional group at conditions which favor formation of the enamine andstoring the resulting liquid aqueous composition.
 2. A process forpreparing an aqueous polymer having functional groups comprisingpolymerizing a monomer mixture which contains acetoacetate monomer atconditions which are incompatible with a functional group and then afterpolymerization, reacting the acetoacetate-functional polymer productwith a compound which has primary amine and the incompatible functionalgroup at conditions which favor formation of the enamine.
 3. The processof claims 1 or 2 wherein the amount of functional amine can be variedover a range of from about 0.1 equivalence to about 1.5 equivalence ofamine, based on the amount of acetoacetate functional group.
 4. Theprocess of claims 1 or 2 wherein the Tg of the polymer is modified bythe addition of functional amines.
 5. The process of claim 2 wherein thepolymerization is a free radical polymerization and the incompatiblefunctional group is selected from the group consisting of mercaptan,olefinic and secondary amine functional groups.